Is there a therapeutic role for selenium in alpha-1 antitrypsin deficiency?
Selenium is an essential trace mineral of fundamental importance to human health. Much of its beneficial influence is attributed to its presence within selenoproteins, a group of proteins containing the rare amino acid selenocysteine. There are 25 known human selenoproteins including glutathione peroxidases, thioredoxin reductases and selenoproteins. Selenoprotein S (SEPS1) is an endoplasmic reticulum (ER) resident selenoprotein involved in the removal of misfolded proteins from the ER. SEPS1 expression can be induced by ER stress, an event that is associated with conformational disorders and occurs due to accumulation of misfolded proteins within the ER. Alpha-1 antitrypsin (AAT) deficiency, also known as genetic emphysema, is a conformational disorder in which the roles of ER stress, SEPS1 and selenium have been investigated. SEPS1 can relieve ER stress in an in vitro model of AAT deficiency by reducing levels of active ATF6 and inhibiting grp78 promoter- and NFκB activity; some of these effects are enhanced in the presence of selenium supplementation. Other studies examining the molecular mechanisms by which selenium mediates its anti-inflammatory effects have identified a role for prostaglandin 15d-PGJ2 in targeting NFκB and PPARγ. Together these ER stress-relieving and anti-inflammatory properties suggest a therapeutic potential for selenium supplementation in genetic emphysema.